The present invention relates to a portable compact radio terminal device and, more particularly, to a portable compact radio terminal device which is suited for a radio mobile terminal and can obtain a high antenna gain.
With recent abrupt advances in performance and miniaturization of mobile terminals, the corresponding techniques have remarkably advanced. As compared with advances in circuit techniques, devices, and the like, however, antennas with higher performance and smaller sizes are difficult to realize. This poses a problem in the design of mobile terminals.
Pagers, which are currently regarded as the smallest of mobile radio devices, are often carried by people. Demands have therefore arisen for antennas that can obtain high gains even when people carry the pagers. Loop antennas are antennas designed to detect magnetic fields, which exhibit no decrease in antenna gain even when the pagers are carried by people. For this reason, many recent pagers use loop antennas in the form of a rectangle or a rectangle with round corners.
With recent advances in miniaturization of pagers, demands have arisen for smaller loop antennas incorporated in the pagers. If, however, a pager is reduced in size, a state-of-the-art loop antenna cannot ensure an antenna loop opening area that is required to ensure the same antenna gain as the current antenna gain. In addition, the antenna tends to be affected by metal parts that interfere with magnetic fields. It is therefore difficult to obtain desired antenna characteristics.